In 1994 I was diagnosed with celiac disease, which led me to create Celiac.com in 1995. I created this site for a single purpose: To help as many people as possible with celiac disease get diagnosed so they can begin to live happy, healthy gluten-free lives. Celiac.com was the first site on the Internet dedicated solely to celiac disease. In 1998 I founded The Gluten-Free Mall, Your Special Diet Superstore!, and I am the co-author of the book Cereal Killers, and founder and publisher of Journal of Gluten Sensitivity.

By Scott Adams

Published on 07/26/1996

Preface: The following information was supplied originally
in 1991 in the form of a letter to Phy

Preface: The following information was supplied originally
in 1991 in the form of a letter to Phyllis Brogden, Chairperson
of the Greater Philadelphia Celiac Sprue Support Group, by Donald
D. Kasarda, who was a Research Chemist with the US Department
of Agriculture at that time. Copies were sent to four other major
celiac patient groups in the US. Dr. Kasarda retired from the
USDA in 1999, but updated the information in February of 2000.
Dr. Kasarda wishes to add the following disclaimer to the information:
These are my opinions based on quite a few years of research
in the area of proteins as they relate to celiac disease. They
do not necessarily represent those of the Agricultural Research
Service, U. S. Department of Agriculture. If you have any questions
or comments regarding the piece, you can address them to Don at:
kasarda@pw.usda.gov

The only plants demonstrated to
have proteins that damage the small intestines of people with
celiac disease are those from wheat, rye, and barley (and the
man-made wheat-rye cross called triticale). Although oats
had generally been considered harmful until 1996, several high
quality studies published since then indicate that oats are
not harmful either in celiac disease or dermatitis herpetiformis.
Some physicians choose not to accept these findings or else
point out that there is some potential problem of contamination
of oats by wheat. The contamination question has not yet been
adequately researched, but may be overemphasized. The three
harmful species are members of the grass family and are quite
closely related to one another according to various schemes
of plant classification (taxonomy). However, not all members
of the grass family damage the intestines of celiac patients.
Rice and corn, for example, are apparently harmless.

Many other grains have not been
subjected to controlled testing or to the same scrutiny as wheat,
rye, barley, oats, rice, and corn in relation to celiac disease.
In fact, only wheat and oats have been extensively studied in
controlled experiments with the most up-to-date methods. If
we accept corn and rice as safe, however, and this seems reasonable
to me, then members of the grass family that are more closely
related to these species (on the basis of taxonomy) than to
wheat are likely to be safe. Such grasses include sorghum, millet,
teff, ragi, and Jobs tears, which appear to be reasonably closely
related to corn. In some cases, there are protein studies in
support of this conclusion, although the studies are not sufficiently
complete to provide more than guidance. Scientifically controlled
feeding studies with celiac patients would provide a better
answer. However, such studies are not likely to be carried out
in the next few years because of high costs and the difficulty
of obtaining patient participation (such studies would likely
involve intestinal biopsy). In lieu of feeding studies, further
studies of protein (and DNA) would provide the next best way
to evaluate my suggestion that millet, sorghum, teff, ragi,
and Jobs tears are not likely to be toxic in celiac disease,
although even such studies are hampered at present by a lack
of knowledge of which sequences in the wheat gluten proteins
are harmful. There is evidence that a few sequences are harmful,
but not all possibilities have yet been tested.

The scientific
name for bread wheat is Triticum aestivum var. aestivum--the first
part of the name defines the genus (Triticum) and the second part,
the species (aestivum). Species falling in the genus Triticum are
almost certain to be harmful to celiac patients. Grain proteins of
these species include the various types characteristic of the gluten
proteins found in bread wheats (including the alpha-gliadins) that
cause damage to the small intestine in celiac disease. Durum wheats
(Triticum turgidum var. durum) used for pasta are also harmful to
celiac patients. Some Triticum species of current concern include
Triticum aestivum var. spelta (common names include spelt or spelta),
Triticum turgidum var. polonicum (common names include Polish wheat,
and, recently, Kamut), and Triticum monococcum var. monococcum (common
names include einkorn and small spelt). I recommend that celiac patients
avoid grain from these species. Also, given their very close relationship
to bread and durum wheats, I think it is unlikely that these grains
would be safe for those with classical allergic responses to wheat.

Rye (Secale cereale)
and barley (Hordeum vulgare) are toxic in celiac disease even though
these two species are less closely related to bread wheat than spelta
and Kamut. They belong to different genera, Secale and Hordeum, respectively,
and lack alpha-gliadins, which may be an especially toxic fraction.

There have been
anecdotal reports suggesting a lack of toxicity in celiac disease
for spelta and Kamut, along with anecdotal reports of the opposite,
at least in the case of spelt-celiac patients who have been harmed
by eating it. Controlled tests would be necessary to draw a firm conclusion,
although they hardly seem necessary insofar as spelt and Kamut should
be considered forms of wheat.

The diagnosis,
sometimes self-diagnosis, of celiac disease is occasionally made without
benefit of reasonably rigorous medical or clinical tests, especially
intestinal biopsy. Individuals who are diagnosed in this
way without rigorous testing may not actually have celiac disease.
Claims that particular foods cause this latter group no problems in
relation to their celiac disease could cause confusion.

Furthermore,
celiac patients who report no problems in the short run with spelt
or Kamut might experience relapse later. There is now adequate evidence
that when celiac patients on a gluten-free diet (that
is, a diet free of any proteins or peptides from wheat, rye, and barley)
have wheat reintroduced to their diets, times-to-relapse vary enormously
among individuals, ranging from hours to months, or even years. And
this is for wheat, presumably the most toxic of all cereal grains
to celiac patients.

Additionally,
the relapse may not be accompanied by obvious symptoms, but be recognized
only by physicians through observation of characteristic changes in
the small intestinal tissues obtained by biopsy. The reasons for the
enormous variability of response times are not known. It may be speculated
that the variability has something to do with the degree of recovery
of the lining of the small intestine on a gluten-free diet, the degree
of stress that the patient had been experiencing (including infections),
and individual genetic differences.

As I have indicated,
all known grain species that cause problems for celiac patients are
members of the grass family. In plant taxonomy, the grass family belongs
to the Plant Kingdom Subclass known as monocotyledonous plants (monocots).
The only other grouping at the Subclass level is that of dicotyledonous
plants (dicots). Some other species about which celiac patients have
questions actually are dicots, which places them in very distant relationship
to the grass family. Such species include buckwheat, amaranth, quinoa,
and rape. The seed of the last plant listed, rape, is not eaten, but
an oil is pressed from the seeds that is commonly used in cooking.
This oil is being marketed as canola oil. Because of their very distant
relationship to the grass family and to wheat, it is highly unlikely
that these dicots will contain the same type of protein sequence found
in wheat proteins that causes problems for celiac patients. Of course,
some quirk of evolution could have given rise in these dicots to proteins
with the toxic amino acid sequence found in wheat proteins. But if
such concerns were carried to a logical conclusion, celiac patients
would have to exclude all plant foods from their diets. For example,
buckwheat and rhubarb belong to the same plant family (Polygonaceae).
If buckwheat were suspect for celiac patients, should not rhubarb,
its close relation, be suspect as well?

It may be in
order to caution celiac patients that they may have undesirable reactions
to any of these foods--reactions that are not related to celiac disease.
Allergic reactions may occur to almost any protein, including proteins
found in rice, but there is a great deal of individual variation in
allergic reactions. Also, buckwheat, for example, has been claimed
to contain a photosensitizing agent that will cause some people who
have just eaten it to develop a skin rash when they are exposed to
sunlight. Quinoa and amaranth may have high oxalate contents-approaching
those of spinach and these oxalate levels may cause problems for some
people. Such reactions should be looked for, but for most people,
buckwheat, quinoa, or amaranth eaten in moderation apparently do not
cause problems. (Buckwheat is sometimes found in mixture with wheat,
which of course would cause a problem for celiac patients.) It seems
no more necessary for all people with celiac disease to exclude buckwheat
from their diets because some celiac patients react to it than it
would be for all celiac patients to exclude milk from their diets
because some celiac patients have a problem with milk.

In conclusion,
scientific knowledge of celiac disease, including knowledge of the
proteins that cause the problem, and the grains that contain these
proteins, is in a continuing state of development. There is much that
remains to be done. Nevertheless, steady progress has been made over
the years. As far as I know, the following statements are a valid
description of the state of our knowledge:

Spelt or spelta
and Kamut are wheats. They have proteins toxic to celiac patients
and should be avoided just as bread wheat, durum wheat, rye, barley,
and triticale should be avoided.

Rice and corn
(maize) are not toxic to celiac patients.

Certain cereal
grains, such as various millets, sorghum, teff, ragi, and Jobs
tears are close enough in their genetic relationship to corn to
make it likely that these grains are safe for celiac patients to
eat. However, significant scientific studies have not been carried
out for these latter grains.

There is no
reason for celiac patients to avoid plant foods that are very distantly
related to wheat. These include buckwheat, quinoa, amaranth, and
rapeseed oil (canola). Some celiac patients might suffer allergies
or other adverse reactions to these grains or foodstuffs made from
them, but there is currently no scientific basis for saying that
these allergies or adverse reactions have anything to do with celiac
disease. A celiac patient may have an allergy to milk, but that
does not mean that all celiac patients will have an adverse reaction
to milk. Again, however, scientific studies are absent or minimal
for these dicots.

A list of my publications
with pertinence to celiac disease follows. Cross-references to the
literature for most of the points discussed above can be found in
these publications.